The US is a constitutional republic and the government operates under the US Constitution. Being a federal union of 50 states, the US president Barack Obama is the 44th US president.

As the oldest surviving federation in the world, the American federalist system is based on 3 different levels of government, as follows: the federal level, the state level and the local level. These 3 governments are the ones handling tax collection. Statistics show that in 2010, the federal, state and municipal governments amounted to 24.8% of GDP solely from tax collection.

The federal government is subject to another 3 branches. The legislative branch combines the Senate and the House of Representatives, thus forming the bicameral Congress. The executive branch is composed of the commander-in-chief of the military and the president. The judicial branch is represented by the Supreme Court.

The main two political parties in the US are the Democratic Party (founded in 1824) and the Republican Party (founded in 1854). The other notable American political party is the Libertarian Party (founded in 1971). The Republican Party is regarded as conservative, thus center-right on the political spectrum while the Democratic Party is considered liberal, thus center-left. The Libertarian Party is not clearly labeled, as they consider themselves more socially liberal than the center-left Democrats, but more fiscally conservative than the center-right Republicans.

In 2012, the Democracy Index places the US at number 21 and the Corruption Perception Index shows the US at number 19.